Looking for the best-value exhaust for the BMW G90 or G99 M5?
This guide compares the Scorpion OPF-back, midpipe and full cat-back exhaust options, explaining which setup is right for your G90 or G99 M5 based on sound, usability and regional requirements.
Introduction
The BMW G90 M5 and G99 M5 Touring represent a new era for BMW’s flagship performance saloon and estate. With huge power, everyday usability and a refined factory setup, it’s no surprise that one of the first upgrades owners consider is the exhaust system. An aftermarket exhaust is one of the most effective ways to unlock more character from the car without changing how it drives day to day.
At R44 Performance, we’ve worked closely with Scorpion Exhausts, a UK-manufactured solution developed with real-world input and hands-on testing. Having installed and run every configuration ourselves, we’re well placed to explain which Scorpion exhaust option is right for your G90 or G99 M5.
Overview: Scorpion Exhaust Options for G90 & G99 M5
Scorpion offers three core exhaust configurations for the BMW G90 and G99 M5. Each is designed to suit different markets, budgets and sound preferences:
- OPF-Back / Axle-Back Exhaust
- Exhaust Midpipe
- Full Cat-Back Exhaust System
If you’re new to aftermarket exhausts, think of these as increasing steps in sound, presence and completeness, rather than simply “loud or quiet”.
Option 1: Scorpion OPF-Back / Axle-Back Exhaust
The Scorpion OPF-back (also known as an axle-back) replaces the rear section of the factory exhaust, from BMW’s designated cut points backwards.
Who is it best for?
- UK and European owners who need to retain OPF filters
- Daily-driven cars where refinement still matters
- Owners wanting a sound upgrade without major changes
Sound characteristics
With the valves open, exhaust gases flow through a larger bore path for a deeper, more purposeful tone. With the valves closed, gases are routed through the rear silencer for a quieter, more controlled sound – ideal for early mornings or longer journeys.
Installation overview
The system installs at BMW’s factory cut points and reuses existing mounts. It’s a straightforward upgrade that retains all factory filtration and sensors.
Street legality
In the UK and Europe, this is the most suitable road-going option as it keeps all emissions hardware in place.
Ideal buyer
If you want a subtle but noticeable improvement in sound without changing the character of the car, the OPF-back system is the safest and most balanced choice.
View the Scorpion G90 & G99 M5 OPF-Back Exhaust at R44 Performance
Option 2: Scorpion G90 & G99 M5 Exhaust Midpipe
The Scorpion midpipe is widely regarded as the best value upgrade in the range.
Why this option stands out
For relatively low cost compared to a full system, the midpipe delivers the biggest increase in sound and presence.
What it replaces
It replaces the centre section of the exhaust, removing restrictive factory components while retaining the original rear silencer.
Sound vs cost
This setup produces a significantly more aggressive tone and sharper response, making it the go-to choice for owners chasing maximum sound per pound.
Regional considerations
In many regions, including the UK and Europe, this setup is restricted to off-road use only due to the removal of the M5’s OPFs. Bypassing the factory OPFs requires coding or stage 2 engine software to prevent an engine management light.
In markets such as the US, where OPF systems are not present, this option is extremely popular.
Why US customers favour it
US-spec cars retain a relatively free-flowing rear section, making the midpipe an ideal way to unlock sound without worrying about valve compatibility.
View the Scorpion G90 & G99 M5 Exhaust Midpipes at R44 Performance
Option 3: Scorpion Full Cat-Back Exhaust System
The full cat-back system combines the OPF-back and midpipe into one complete solution.
Who should choose this option?
- Owners wanting the most complete Scorpion setup
- Drivers looking for maximum sound, aesthetics and uniform pipework
- Those who want the system to look as good underneath the car as it sounds
Sound, appearance and completeness
With brand-new pipework from the primary connection points to the exhaust tips, this configuration delivers the fullest sound profile Scorpion offers, alongside a much cleaner and more purposeful appearance.
Why this is the ultimate setup
It removes any compromise between sound and design, offering a cohesive system engineered to work together from front to rear.
Shop the Scorpion Full Cat-Back Exhaust System for G90 & G99 M5 at R44 Performance
Which Scorpion Exhaust Is Right for Your G90 / G99 M5?
Q: I daily drive my car in the UK or Europe – what should I choose?
A: The Scorpion OPF-back exhaust is the best option, offering improved sound while retaining road legality and refinement.
Q: I’m a US customer chasing maximum sound.
A: The Scorpion midpipe offers the biggest transformation and works perfectly with US-spec cars.
Q: I want the best value upgrade overall.
A: The midpipe delivers the largest sound increase for the cost and is the team favourite for impact per pound.
Q: I want everything – sound, looks and completeness.
A: The full cat-back system is the ultimate Scorpion solution for the G90 and G99 M5.
R44 Performance Exhaust Packages
For customers who want a proven setup without piecing components together, we’ve created complete exhaust bundles.
R44 BMW G90 & G99 M5 Enhanced Sound Package (2024+)
For customers who want a balanced, well-tested sound upgrade without overcomplicating the setup, this package delivers a noticeable improvement while retaining everyday usability.
View the R44 G90 & G99 M5 Enhanced Sound Package
R44 BMW G90 & G99 M5 Exhaust Midpipe & Carbon Fibre Tailpipe Package
A popular choice for customers wanting both sound and visual impact, combining the aggressive tone of the midpipe with upgraded tailpipe aesthetics.
View the G90 & G99 M5 Midpipe & Carbon Tailpipe Package
Installation Experience & R44 Insight
We’ve installed every Scorpion configuration in-house and were involved in early development feedback. The systems are designed around BMW’s factory cut points, making installation logical and repeatable. Sensor bungs and connections are thoughtfully placed, with provisions for different regional specifications, including markets without OPF systems.
From a practical standpoint, these are well-engineered exhausts that fit as expected and deliver exactly what customers are looking for, whether that’s refinement or maximum presence.
Final Recommendation & Conclusion
Scorpion offers one of the most versatile exhaust line-ups available for the BMW G90 and G99 M5. Whether you want a subtle daily-friendly upgrade, the best value sound improvement, or a full system that transforms the car, there’s a clear option to suit your needs.
Speak to R44 Performance for expert advice on the best G90 or G99 M5 exhaust setup for your build.
